Automatic controllable pitch propeller



May 26, 1942. e. r. LAMPToN r-:rAL' 2,234,154

v AUTOMATIC CONTRULLABLE FITCH PROIELLER Filed July 16, 1937 '7 ShB9tSShBBt l May 26, 1.942 G. 1'. LAMP'roN ETAL 2,284.154

AUTOMATIC CONTRQILLABLE FITCH PROPELLER rlled July 16, 1937 '7 sheets-sheet 2 May ze, 1942.

G. T. LAMP'roN ETAL .AUTOMATIC CONTROLLABLE FITCH PROPELLER Filed July 1e, 1937 7 Sheets-Sheet 3 l hoe/220725 May 26, v1942. G. r. LAMProN :TAL

AUTOMATIC CONTROLLABLE FITCH PROPELLER 7 Sheets-Sheet 4 Itza] Filed July 16, 1937 w W M May 26 1942 G. 1". LAMP-mu arm. 2,284,154 y AUTOMATIC GON'IROLLABLE PITCH PROPELLER Filed July 16, 193;? I 7 Sheets-Sheet 5 g r. M v w uw m Nw, g, liniull, @NN

H l: 'e Ww May 26, 1942.. G. 1. LAMP'roN :TAL 2,284,154

Aumoxmrc: connonmm rusa PRQPELLER Filed July' 16, 1937 7 'sheets-sheet 6 May 26, 1942. G. 1'. I AwnroN am.

AUTOMATIC CONTROLLAVBLE PITCH PRQPELLER Filed .my 1 6. 1937 ,'v sheets-sheet 'f 4Patented May 2 6, 1 942 I A AUTOMATIC coN'rBoLLALE Piron PnorELLEB.

Glen T. Lampton, Paul F. Hackethal, and Arthur T. Briggs, Williamsport, Pa., assignors, by mesne assignments, to The Aviation Corporation, New York, N. Y., a corporation o Delaware Application July 1s, 1937, serial No. 153,926

(C l. 17o- 163) 13 Claims.

The invention relates to hydraulic controlling means for variable pitch-Propellers.

'I'he objects of the invention are to provide an improved hydraulic control in which: a pump responsive to variations in engine-speed is used to control the valve which governs the pressure of uid for controlling the variable pitch-mechanism; a pulley for actuating the pitch-change gearing is automatically controlled for pitchchanges; gear-pumps are used to produce characteristic changes which follow the pressure lines desired better than volume lines and cause the pressure to respond more quickly to changes in the engine-speed; the pressure dierential between uid from two gear-pumps is utilized for eiiicient and quick variation in pressure responsive to speed-changes in the engine; the. pump, automatic pressure-control valve, speed-control valve and pressure relief valves are all included perspective of the -driven element of the friction gearing. Fig. 8 is a section on line 8-8 of Fig.

1. Fig. 9 is a section on` line 9-9 of Fig. 4.l

Fig. 10 is a section on line lil-l0 of Fig. 8.

Fig. 11 is a d etail section on line II-II of Fig. 8

of the pivotal mounting for the shifter yokes for the friction pulley. Fig. 12 is a detail perspective of said pivotal mounting. Fig.' 13 is a longitudinal section through the hydraulic pumping and control unit, Fig. 14 is a section on line |4I4 of Fig. 13. Fig. 14fL is a detail perspective of the pitch-fixing valve. Fig. 14b is a plan of the reversible plate in the governor-unit. Fig. 14 is a section of one of the bi-metallic washers applied tothe safety valve seat. Fig. 15 isa perspective of the body of said unit. Fig. 16 is a perspective of the gear-pump for supplying uid for actuating the automatic pressure-control valve for the pitch-change control. Fig. 17 is a perspective of the plate imposed on the pump shown in Fig. 16. Fig. 18 is a perspective of the actuating pump for the hydraulic fluid for shiftin a unitary assembly for application to the 30 ing the friction-pulley of the pitch-change mechhousing on the engine; the governor-unit conanism. Fig, 19 isl a perspective of the top plate taining thepumps is provided with a reversible of the pumping unit. Fig. 20 is a perspective of plate for adapting the govemor-unit for operathe bottom plate or head for the body of the tion with either a right or left-hand engine withpumping unit. Fig. 21 is a sectional perspective out change in the gearing for driving the unit; 15 illustrating some of the ports in the body of the governor-unit is built up of a body and a the pumping unit. Fig. 22 is a perspective illusseries of plates for ready assembly and disassemtrating other ports in the body of the pumping bly for inspection or repair; a check-valve conunit. Fig. 23 is a section on line 23-23 of Fig. trolled by one of the blades is utilized to limit the 13. Fig. 24 is a section on line 2li-24 of Fig. 13 pitch-variation of the blades; and other objects :i0 through said valve. Fig. 25 is a section on line which will appear from the detailed-description. 25-25 of Fig. 13. Fig. 26 is a section on line The invention consists in the several novel fea- 26-26 of Fig.` 24. Fig. 27 is a diagram of the tures which are hereinafter set forth and are fluid connections of the control system.

more particularly dened by claims at the con- The improved hydraulic control mechanism is clusion hereof. exemplied with an airplane propeller compris- In the drawings: Fig.. 1 is a longitudinal secing an engine-driven shaft a, a hub b keyedto tion of a propeller embodying the invention. the shaft, and propeller-blades c provided with Fig. 1a is a detail section of the valve for limit- Shanks supported in ball-bearings c2, c3 in the ing the pitch reduction'. Fig. 1b is a perspective hub. Shaft a is journaled in ball-bearings a' in of the device for opening the low-limit pitch 40 a stationary housing a2. Outward thrust-memvalve. Fig. 2 is a longitudinal section, illustratbers c4 retain the blades in the hub. ing the pivoted friction-pulley set for driving the A bevel-gear segment c5 is fixed to the inner pitch-change gearing to decrease the pitch of the end of each blade c. A gear-ring d rotatable in blades, parts being shown in elevation. Fig. 2fil f the hub l)l has external teeth d3 which mesh with is a similar view illustratingthe friction-pulley segments c5 on all of the propeller-bladesl to roset for increasing the pitch of the blades, parts tates the blades for pitch-variation. Gear-ring being shown in elevation. Fig. 3 is a sectional d, journaled on ball-bearing 3l, is carried in the perspective ofthe gearing between the eccentric `hub and has an internal series of gear-teleth d' and the gear-segments on the propeller-blades. at its inner end. A gear-ring' e with internal Fig. 4 is a transverse section on line 4-4 of Fig. gear-teeth e corresponding to those on gearring d is fixed to the inner projection of the hub portion b", by means of a flange e4.

The pitch-change gearing comprises: a friction driving-element 20 integral with sleeve 2| which surrounds the hub portion b5, is locked to the hub b which rotates with shaft a, and is pro vided with a radial fiange having an annular convex driving face 23 on one of its side faces; a complementary friction driven element 24 integral with a sleeve 25 journaled on sleeve 2| of driving element 20 and provided with an integral radial flange having an annular convexv frictionface 21` opposite and spaced from the'frictionface 23 of elem'ent 28; and a friction-pulley 28 which has conoidal friction-faces 29 and 30 on its opposite sides which engage, respectively, the convex driving-face 23 andthe driven face 21 to drive element24 from element 20. Pulley 28 is pivotally mounted, as hereinafter described, so it can be angularly set to increase or decrease the speed of the driven element 24 relatively to the driving-element 20, the shaft a and hub b, which rotate together, by engaging the pulley with the driving face 23 and the driven face 21 at relatively different radii. Driving element 20 is confined against longitudinal movement on hub portion b between one race 32 of the bearing 3| and a collar 3P. A series of balls 34 between the outer end of hub 25 of driving element 24 and race 32 receives the forward thrust on element 24. Y

Driven element 24 has an integral eccentric 4| on its outer periphery. A gear-ring h, journaled on ball-bearings h and concentric with the eccentric 4| has a series of external Iteeth h2 meshing with theinternal teeth e of ring e and 'a corresponding series of teeth h3 meshing with the teeth d' of ring d. External teeth h3 are at least.one less in number than h2, and h.2 and h3 are respectively at least one tooth less in number than the corresponding series of teeth onrings e and d. All of the teeth h2, h3, d1, and e1 are of conjugate form adapted for positive driving without interference .when rolled one upon the other as the result of the bodily rotation of eccentric 4| and the resultant rotation of the ring h around said eccentric. Each rotation of eccentric 4| relative tothe hub causes teeth h2 to traverse the internal teeth e1 on the ring e which is nxed to the hub b, and by reason of the lesser number of teeth on h2 on the eccentric ring h than on the fixed ring e, the said eccentric ring h will rotate relative .to the hub and in the direction of rotation of the eccentric 4I an angular distance corresponding to one tooth on h.2 if one is the difference in number of teeth between h2 and e. At the same time teeth h3 on eccentric ring h are traversing the internal teeth d on rotatable ring d and by reason of the greater number of teeth d' than h3 the said rotatable ring d will rotate relative to the eccentric ring h and in a direction opposite to the rotation of the eccentric 4| an angular distance corresponding to one tooth on h2 if one is the difference in the number of teeth between d and h3. The relative motions between the eccentric ring h and the fixed ring e and between the said eccentric ring and the rotatable ring d are in opposite directions and the net angular distance moved by the rotatable ring d relative to the ring e flxed to the hub is for one rotation of eccentric 4| relative to the hub b the din'erence between the angulardistances corresponding to one tooth of h.2 and one tooth of h3. Rotation of eccentric 4| in or relative to the hub rotates gear vring d in the direction of rotation of said eccentric and rotates meshing segments c5 and blades c on their axes with a large mechanical advantage for pitchvariation. When the element 24 and eccentric 4| rotate with the hub and not'relatively thereto,

.the pitch-change gearing will remain neutral and keep the blades at their set pitch. The driven element 24 is provided with an integral counter-balance 25 to balance the eccentric on element 24. Friction-faces 23, 21 are outwardly divergent and the friction-faces of pulley 28 are convergent to permit the pulley to be angularly adjusted while both of its faces remain in driving contact with faces 23, 21. When no pitchchange is desired, the axis of pulley 28 is parallel to the axis of shaft a, it contacts faces 23, 21 on equal radii from the axis of shaft a and they contact pulley-faces 23, 30 on equal radii. The pulley will then be neutral and rotate idly without producing any relative rotation between elements 20, 24 which will rotate with the hub while pulley 28 will rotate on its own axis without effecting any relative movement between said elements. Gear-rings d, e, h will'all rotate with the hub b without operating the pitch-change gearing, so that the pitch of the blades will re- Vcarried by a hub 43.

socket joint 45 between hub 43 and a stud 46- main xed.

When pulley 28 is swung in one direction, as shown in Fig. 2, the radius of the contact on driving face 23 is increased, the radius of its contact on pulley-face is decreased, the radius of contact on pulley-face 30 is increased, and the radius of contact on driven face 21 ofelement 2| is decreased. This will cause the pulley 28 to rotate element 24 and eccentric 4| in the hub, in the direction of rotation of the propeller so that the eccentric gear-ring h will be rotated insidev of gear-ring e and advancevthe gear-ring d and drive it faster than the hub. This will rotate segments c5 to decrease the pitch ofthe blades.

When pulley 28 is tilted in the opposite direction (Fig. 2*) the radius of the contact on driving face 23 will be decreased, the radius of the contact on pulleyeface 29 will be increased, the radius of the contact on pulley-face 3l will be decreased, and the radius of the contact on the face 21 of driven elementv24 will be increased. In this position element 24 and eccentric 4| will be rotated in the hub b in the direction opposite to the rotation of the propeller. 'I'his will cause the gear-ring d to be rotated with the hub by eccentric 4| at a lower speed than the hub b. The rolling movement of the gear-ring h in ring e will then effect, through vgearfteeth h3 and gear-teeth d' on'ring d, rotation of segments cs to increase the pitch of the blades.

Pulley 28 is -journaled on a ball-bearing 42 A universal or ball-andwhich is fixed to the cross-member of a yoke 44, supports the hub and pulley 28 for variation of its angular relation with the convex frictionfaces 23, 21. Yoke 44 is pivoted on coaxial pintles .48 to swing transversely of pulley 28. When yoke 44 is swung in either direction, the axis of the joint 45 will be shifted longitudinally of shaft a and the angular relation between the frictionfaces on pulley 28 and the convex friction-faces 23, 21 will be varied to vary the radii of the contacts between said faces for varying the speed of rotation of element 24 and eccentric 4| in the hub. The outer portion of pulley 28 remains between elements 20, 24 while its axis is shifted by stud 46. The universal joint 45 and the engaging friction-faces of pulley 28 and -friction-faces 2,284,154 elements 28, 24 for speed variation and to permit both faces of pulley 28 to be in operativev contact with faces 23, 21, respectively.

in the front-wall lof housing 53. By rotating the y cap, the pin can "be adjusted to position limit- Fluid pressure mechanism for shifting yoke 44 .to control the angular settings of pulley 28 comprises a cylinder 6I integrally formed with a head 52, a piston 82 in the cylinder, a stem 83 pivoted at 44' to yoke 44 and held by a spring 84 in thrust-engagement with said stem. Spring 64 is between a flange on the inner endof stem 83 and a cap 64 fixed to head 52.

Pulley 28 and the portion 'ofelements 28, 24 engaged thereby and the piston and cylinder for shifting pulley 28 are disposed around portion b5 of hub b between the hub-.portion b" whichv surrounds gear-rings d, e and the casing al and are enclosed by an intermediate housing 53 which is.

to the eccentrices or arms 49. When yoke 54.

is swung on studs 58 as an axis, pivots 48 on which yoke 4'4 is pivoted, and the inner pivotedA end of yoke 44 will swing to and from the axis of the driving and driven elements 28, 24 while the yoke 44 is free to rock on pivots 48 and in the socket of the universal joint 45. Conoidal faces of pulley 28 are free to adjust themselves4 for the varying contact with the faces 23, 21 on dierent rad. Yoke 54 isadapted to shift the axis of pulley 28 slightly to and from the driving and driven elements to provide for proper contact on dilerent radii between the pulley-faces and the driving and driven elements.

To provide for loaded engagement between the pulley 28 and the friction-surfaces 23, 21 in all positions of the pulley, yoke 54 is operable by fluid pressure means which comprises a cylinder 18 in head 52, a piston 1|, and a spring 13 between said piston and yoke 54. Oil under pres- -sure corresponding to the pressure in cylinder 6| iiows toV the closed end of cylinder 18 from duct -|59 which supplies oil to cylinder 6I. A stop-ring 12 limits the outward movement of piston 1|. The spring 13 and the iiuid pressure in cylinder 18 apply yielding` pressure to the yoke 54 to rock the yoke around fixed pivots and move pivot-pins 48- of yoke 44 toward the axis of propeller-shaft a, so that the friction-faces 28', 29 of pulley 28 will be forced into engagement with frictionsurfaces 23, 21 in all angular settings of the pulley. Spring 13 is suicient, under variations of pressure in cylinder 6|, to exert sumcient yielding pressure on yoke 54 to force pulley 28 against surfaces 23, 21. The proportions of spring 13 and the travel of piston 1| allow complete unloading of the pressure between pulley 28 and .surfaces 23,. 21 when the fluid pressure is removed from cylinder 18.

Pulley 28 and its mounting, including yokes 44, 54 and their operating mechanism,'are mounted on'liead 52 which is secured to the intermediate housing 53 to permit the unitary -1 removal of all 4of the parts carried by sai/diiead for inspection stops 8| onpin 88 relatively to the element' The casing of the governor for the fluid for controlling the pitch-change mechanism is built up of a body-member (Fig. 15); a plate 88 (Fig. 16) which fits over body 85 and forms a casing for a pressure control pump consisting of intermeshing gear-elements 81, 88; a reversible plate 89 (Fig-17) which ts over plate 88; -a

plate 98y (Fig. 18) which ts over plate 89 and' forms a housing for an actuating pump consisting of gear-elements 9|. 92; a cover-plate 93 (Fig. 19) which iits over plate 98; anda bottomplate 94 (Fig. 20) which fits on the bottom of. and is secured by bolts 91', to member 85. Member 85 and plates 88, 89, 98 and 93 are secured together in'superposed relation, by bolts 95 to -iorm a unit which is adapted -to be secured to the lower portion of casing a2 by four bolts which pass through holes 96 in said body and series of plates. A head 99 issecured between the top of the governor casing andcasing a.-

Gear-elements 88, 92 are coaxial and are driven by a sleeve or hollow shaft 91 (Fig. 13)

which is integral with element-l 92, keyed to ele- I propeller-shaft a; av gear I8| which is mounted on a stud-shaft |82 supported in housing a2 and meshes with pinion |88; a pinion |83 fixed to rotate with gear 8| and meshing with an internal gear |84 which is rotatable around shaft a; a gear |85 fixed to gear |84; a pinion |88 meshing with gear 85; a bevel-pinion |81 rotating with pinion |86; and a bevel-pinion |88 on the upper end of hollow shaft 98, to which pump-shaft 91 is detachably coupled. Gearelements 81, 9| are journaled on a-hollow shaft ||5 which fits in body 85 and plates 89,. 93.

Oil under pressure from the engine iiows through a duct H2 in casing a2, a duct ||3 in head 99, an arcuate groove ||4 in the. top of `plate 93 which registers with the bore of hollow shaft |5. Shaft H5, through which oil passes from casing a2 to the. governor-unit, is closed at one end, except for a' small orifice ||5. This reduces the amount of oil supplied by the engine and at the same time minimizes the effect of oil engine pressure in the governor-unit. By returning the oil from the governor-unit to the inlet side of the pumps and restricting the amount of oil supplied from the engine, any oil not necessary in the-governor will iiow back to or remain in the sump without passing through the pumps and the only oil required from the engine ls sumcient to make up for the loss or consumption in the governor-unit. In the event that the governor is used 'with an engine which supplies governor oil from a sump at atmospheric pressure,4

I which extends vertically of said plate. From port |20 oil flows (Fig. 24) upwardly rto the inlet space 90* at one side of gear-elements 9|, 92 of the actuating pump and also downwardly to the inlet-space 86"l between gear-elements 81, 88 of the pressurecontrol pump. These ducts continuously deliver oil under pressure from the engine to both pumps in the governor-unit.

'I'he actuating pump which comprises plate 90 and'gear-elements 8|, 92 functions to deliver oil under pressure for shifting the pulley 29 to control the operation of the Vpitch-change mechanism and the pressure control pump which comprises plate 86 andgear-elements 81,v 88 forces oil under pressure which varies according to propeller speed, to avalve |3| for governing the pressure of oil in the line to cylinder 6| of the means for shifting pulley 28 and the cylinder 10 for loading said pulley to engage friction-elements 20, 24 of the pitch-change gearing.` Oil from the actuating-pump is forced from the outlet side 90b of the chamber in plate 90 through a vertical port |25 in plate 89, port |26 which extends through plate 86 and registers with port |25, port |21 in body- 85 which registers with port |26, cross-port |28 (Fig. 21) in body 85, a

branch-port |29, chamber |30 (Fig. 13) around.

valve-casing |32 which contains the slidable pressure-controlling valve |3 ports |33 in valvecasing |32, and ports |34 which are controlled by valve 3| to control the pressure of the oil to the actuating line for cylinders 6|, 10.

From ports |34 the oil passes under reduced pressure through port (Figs. 21 and 26) to the seat of three-way cylinder valve |4| in body 85, through port |42 in valvev |4|, oblique port |44 in body 85 (Fig. l5), port |45 in plate 86, port |46 in plate 89 (Fig. 1'1) through port |41 in plate 90, port |48 in cover-plate 93, a duct |49 in housing a2 and through head 99, annular channel |50 around an oil-ring 2I on shaft a, duct 66 in housing a3, port`62 in housing 53, pipe 68 and a duct 69 which is branched todeliver oil under governed pressure into cylinders 6|, 10.

The bearing for hollow shaft 91 in the governor-body extends below the lower end of said shaft to form a chamber |-1| to which oil returned from the actuating and governing lines is delivered. From chamber |1| vthe returned oil passes into the bore of shaft 91 from which it passes to the inlet sides of the gear-pumps or to the casing a2 for recirculation. The means for delivering oil from chamber |1| and the bore of shaft 91 to the gear-pumps comprises a slot |209 which connects the hole |2||b in the reversible plate 89-.through'which shaft 91 extends and port ||9. Said hole |20b is of suflicient diameter to provide a passage for oil around said shaft. Ports |20 deliver oil from the lower end of shaft 91 to the hole |20", in plate 89, from which it can flow through slot |20a to the port ||9, which delivers the oil to the inlet sides of the gear-pumps. This permits the oil to pass from chamber |1| to the governor-pumps for recirculation of the oil and avoids excessive use of the engine-oil. f

Oil from chamber |1| can also pass back to the casing at2 through the yupper end of shaft 91. A light check-valve |98 is adapted to close the upper end of the bore of hollow shaft 91 and is held against an upwardly facing seat by a spring |99. A plug 200 having a port therethrough is screwed into the upper end of shaft 91 and serves as an abutment for spring |99. This valve |98 insures against air being sucked into the governor through the drive-shaft in lieu of oil through the regular inlet ||4, in the event that oil is dis-` charged by the governor at such a rate that the make-up oil-is not supplied in sufficient quantity to maintain the entire governor at or above sump pressure.

Some of the oil in the line between cylinder 6| and automatic valve |3| passes under said valve, A

` |81 connects the reduced end of valve-seat |15 seat with channel 39 around the casing for bellows |69. Oil which passes valve-ball |13 flows from chamber |14 through duct |80 to chamber |1| for recirculation.-

f In practice, it is desirable to limit the maximum pressure in the oil-line between the actuating pump and the regulating valve |3|, to say lbs. For this purpose, a check-valve is embodied in the governor-unit and comprises a ball |64 held by a spring |66 against a valve seat |85 in chamber |61 which is formed in body 85 and closed by a screw-plug |68. Oil from the pressure side of the actuating gear-pump 9|, 82 passes (Fig. 24) through port |25 in reversible plate 89, -one of the ducts |26 in plate 88, ducts |21, |28, |21*L to the inlet side of check-valve |65. From check-valve chamber |61- the oil vwhich passes the check-valve |64 flows through a port |10 to the chamber |1| for recirculation.

Oil under pressure from the pressure-control pump (86, 81, 88) whichis variably responsive to the speed of the engine and propeller, is discharged from its outlet side 86b and flows through port |54 in plate 89 (Figs. 13, 17), port |54 in plate 86, duct |54 in body 85, chamber |55 around a needle-valve 58, duct |51 in body 85, groove |58 in the top-face of bottom-plate 94, and an upstanding pipe |59 into bellows |36. Variation of pressure of oil from the pressurecontrol pump expands and contracts the bellows |36 to move valve |3| to vary' the pressure in the line to cylinders 6|, 10 for controlling the operation of the pitch-change gearing, as aforesaid. Needle-valve |56 is mounted in the bottom-plate 94 and is adapted to be screwed to and from a seat |60. A wheel |62 is xed to the lower end of the stem 'of valve |56 for connection to a cable which is operable from the pilots cab to manually adjust the valve and correspondingly control the speed. Seat |60 is formed in a member |60' which is slidable in the lower end of cylindrical chamber |1| and is pressed upward by a coilspring' |.6|. This seat actsV as a safety devicein sure in bellows |36 from the oil-line supplied by the pressure-control pump. When the pressure in the bellows is increased, valve |3I. is raised,

Athe area of the passage between the ',upper ends oil through plate 86 to one of the ducts |21 from the pressure-side of the actuating-pumpwhile plate 489 is in either of its alternative positions. Body 85 is provided with a duct |21 at either side communicating with ports |26 @and cross-- connected by duct |28 so that, in either position of reversible plate 89, the oil will be forced to the governor-valve by the actuating-pump. A

.portr |46 is provided at either'side of plate 89 so that, in either of its alternative positions,

communication will be maintained between port |44 and port |48 which leads to the actuating-line for cylinder 6|.

of passages |34 and said valve is decreased and the area of the passages |34 belowvalve |3| is increased. Thus, increase of pressure in bellows |36 will reduce the volume of oil flowing to, and increase theoutow from the line to, cylinders 6|, 10 and proportionately reduce the pressure in said cylinders to actuate'the pulley 28 to operate the pitch-change gearing for a pitch-increase. When the pressure in bellows |36 is reduced, valve |3| will move downwardly, increase the gap between its upper end land 'the top of passages |34 and decrease the gap between its lower end and passages |34. This will increase the Vilow to cylinders 6|, 10 and reduce the volume of the oil returned for recirculation through chamber |35, ports |38,'channel |39, porty |81, and

vcheck-valve |13 to chamber |1|.

Three-way valve |4| fits in a cylindrical socket in body 85 and is provided with a stem to which arm |82 is xed and so the valve may be controlled by a suitable cable |83 from the pilots cab. Thisvalve is adapted to close the oil-line between the governor-valve 3| and-cylinders 6|, when it is desired to operate the propeller at a fixed pitch, and simultaneously drop the pressure in the cylinders 6|' and 10 to disengage the fric- |40, |44, longitudinal groove |4| in its periphery connects port |44 to chamber |1| for the purpose of relieving pressures in the control system.

Plate 89 is insertable and reversible to adapt the govemor-unit for use with either a right or left-hand engine Without changel in. the gearing for driving the pumps. When said plate is' in the position illustrated in Fig. 17, port will deliver oil into the side 90* of the actuating pump-chamber and the discharge will be at the opposite side 90b. The inlet and outlet sides 898, 89 of the pressure-control pump below plate 89 will be correspondingly disposed. When the engine is such as to drive the pump-gears in the opposite direction from that indicated by the arrows, plate 89 will be inverted and reversed to position the port |20 at the opposite side of the pump-chambers, which will reverse they ow loi! oil through the pump-chambers. Inlet port |20 is located sothat, upon reversal of plate 89, it will ndeliver oilinto the oppositely disposed sides 86", 90b of the pump-chambers.

When the plate 89 is reversed, the inlet end of duct |54 will be in communication with the side 86a of the pump-chamber in said plate and its outlet end remains in registryvwith port |54* This exemplifies a governor-unit comprising one or two pumps for actuating the pitch-confY trolling mechanism, which is adapted, .without change of the gearing, for operation with either la right or left-hand engine. i

The invention comprises automatic low-limit pitch-controlling means for the blades. Oil from channel |50 also passes through oil-ring |2| on shaft a which is provided. with an annular groove and port |85 for delivering oil under controlled pressure from channel' |50 to duct |86 in shaft ,a. Chamber |81 is formed between wall b9 of the hub and sleeve |88. Pipe |89 andduct |90 in sleeve |88 deliver oil under governed pressure from duct .|86 into chamber |81. Check-valve |9| is carried in a casing |9| which is' mounted in-wall b9 of the hub. When open, this valve will permit o'il from annular channel from which oil is delivered to-cyl inder 6|, to flow into the gear-chamber in the hub. From this chamber oil is returned through duct'a.8 to housing a2. fixed to the shank of one of the blades, by means of bolts (not show n) passing through the slots |92, is provided with abutment |93 which is adapted to engage stem '|94 on the check-valve |9| when the blades reach their' low pitch-limit, at which time the abutment lwill open valve |9| and permit oil to drain from channel |50 (which is in communication with cylinders 6|, 10) through shaft a, ducts |89 and |90, chamber |81 and valve-casing |9| to the gear-chamber from which it flows through duct a8 back to casing a2;

' 'I'he pressure in the liiie'to cylinders 6|, 10 will then be reduced so that operation of .the pitchchange gearing to reduce the pitch .will be automatically discontinued. This exempliiies auto- `matic means controlled by the governed preslsure of oil for controlling the pitch-change mechanism for limiting the pitch-limit in one and duct |54", which lead to the bellows. Plate' that lport direction. Since the blades c are interconnected by gearing, only one valve |9| is necessary.

Any suitable fixed -stop may be used for the high pitch-limit, and, if desired, may be set to allow the blades to assume position substantially parallel to the axis of the shaft a.

The operation of the improved automatic governor for the control of the pitch-change mechanism will be as follows o When the engine is in operation at the optimum speed, the governed pressure in cylinder 6| will be such that the pulley 28 will be held in its neutral position with its faces 29 and 30 engaging the friction-faces 23, 21 of the variable speed pitch-gearing on equal radii. The pulley will run idly on its own axis without eifecting any change in the pitch-change gearing.l The actuating-pump of the governor-unit-will keep` the oil inthe line which delivers it to the con-f trol-valve |3| A under the desired predetermined pressure. The pressure-control pump, loperating proportionately to engine-speed, will control A cam |92 adjustably.

andreturntothecasingal actuating to retain the pulley!! in'its neutral position. Ii* the speed oi-the engine', either on account of. its load, 'or for other reasons. should be rednced,.thespeed 'of the control-pimp will be correspondingly reduced. which will correspondingly reduce the pressure of oil in'bellows i".

Thiswill causevalve iti to dropand increase the ilow of oil from the actuating-pump past saidvalvetothelineleadlngtocylinderi and increase the pressure therein. This increase of Vpressure in cylinder i will cause its piston O2 to swing pulley 28 into positionshown in Fig. 2.- 'The pitch-chante Bearing will 'then be Operated I l 2,254,154 the valve iti and the pressure ofthe oil in the line between saidvalve'and cylinder thebladesto varytheir-pitchamtarygeariiuid.

the blades to var! their ith. a iluld lllmii' means actuatedbyiiuldpressiuefromsaidpump for actuating the gearing for pitch-changes. a

`.pumpresponsivetothespeedofthepro peller, and'means controlled by variations ofthe' Dressumproducedbythesecondpumpiorcom.

trolling im theiiuidpressuretdactuatethegear.

blades oi a variable pitch propeller comprising variable speed gearing for shitting the Ditch of pump, means actuated by iluidjpremue'irom to reduce the pitch oi the blades and the load upontheengine. Ifthe bladesareshii'tedto the low-pitch limit before the engine has accelerated, abutment it! on one of the propeller-blades will open valve iti. which will permit oil from -the annular channel ISI (from which the oil also ilows to cylinderli) to ilow 'through said'valve This will reduce the pressure in cylinder 'ti suiliciently to' cause pulley 2l to be returned toits neutral position .and discontinue the pitch-reduction.

. When the speed of the engine increases above optimum, the pressure oi.' oil in bellows i8 will be increased. This will lii't valve iti to reduce the ilow to, and the pressure oi the oil in. cylinder Il suiciently -to cause piston 62 to shii't pulley Il into position shown in Fig. 2a. This will render the pitch-change gearing operativel to increase the pitch ofl the blades until the 'engine-speed is reduced to the optimum. In this manner, the pitch-change gearing is automatically controlled for pitch-increase or decrease .by the hydraulic govemor-mechanism.

When it. is desired to .operate the Propeller at a xed pitch, the operator will rock valve |42 to cui: oil the delivery of oil to cylinders Il, III for the purpose of relieving pressures in the control-system. The manual adjustment of needlevalve I. controls the pressure in the line between A the pressure'control-pump` and bellows |30 so that the speed to be maintained under automatic pitch-control may be variedfas desired. 'I'he spring-loaded valve-seat liln for needle-valve lit serves as a safety vagainst excess pressure produced by the-pressure-control pump. If the pressure inthe line between the actuating-pump and the govemor-valve lli becomes excessive, check-valve i will open and return the excess tothe gear-pumps for recirculation.

' The invention is not to be understood as re-v stricted to the details set forth, since -these may be modiiled within the scope loi? the appended claims. without departing from the spirit and scope oi the invention.

Having thus described the invention, what we claim as new and 'desire to secure by Letters V`Patent is:

1. Mechanism for shifting and controlling the blades of a variable pitch propeller comprising variable speed gearing for shifting the .blades to vary their pitch, ycomprising' a variablespeed pulley, iluid pressure means for actuating the pulley 'lior pitch-changes, a' variable pressure pump responsive to the speed of the propeller, and means controlled by variations of pressure produced by the pump for controlling the pressure means to actuate the pulley.

2. Mechanism for shifting and controlling the blades of a variable pitch propeller comprising said iiuid pump for 'actuating the gearing for pitchchangesa second pump responsive to the variations of. the Produced bythe second pump for controlling duid pressure to actuate the gearing.

4. Mechanism for muon; ma eontmmng un blades o! a variable pitch Propeller comprHng variable speed searing for shifting the pitch-ot the blades to vary'their pitch, a fluid pump. means actuatedbviiuid pressure from said pump for actuating the searing for pitch-changes," a rotary gearpump responsive to tbe speed of thepropeller, and means controlled by variations otthepressureproducedbytherotary'gear pump i'or controlling the nuid pressure to actuate thg'su hamm f non .f ec or and con .the blades ioi.' a pitch Propeller comprising variable speedfsearlng forv shifting the pitch Ao! thebladestovarytheirpitch-.arotarygear iluid pump,Ameans actuated by uuid pressure from the pump for actuating the gearing forV pitch-changes, a second rotary gear pump resplsivetothespeedofthcplvcpcllcnandmeamcontrolled by variations of the pressureproducedV pump, andacasingfor said pumpsandvalvev propeller, a valve for controlling the actuatingu iluid responsiveto pressure from the second comprising a body-containing the valve and sciraetl; sections containing said pumps, respec- 7. Fluid pressure means for controlling and shifting gearing. for varying'the pitch oi avari-l able'pitch propeller comprising a gear pmnp for uid'for controlling said gearing, a second gear pump responslveto variations in the speed oi the propeller, a valve' for controlling the actuating huid responsive to pressure from the second pump, a manually controlled valve. and a casing for said pumps and valve comprising a containing said pumps. respectively.

8. In iiuid pressure means for controlling and shifting gearing for varying the pitch of a var- .iable pitch ,propeller,' the combination of a governor body provided with inlet and outlet passages ior iluid. a gear pump in the body for forcing nuid tocontrol said gearing, a valve in -the;body ilorv controlling the pressure of iiuid to said gearing, iiuid pressure-meansin said body for controlling the governor valve, a manually controlled valve for .controllingthe pressure of iluid for operating the pressure control valve' variable speed gearing for sluiting the pitch oi comprising a needle and a movable seat operable s: eenanimfor ahnung and controllingv uis 9. lIn fluid pressure means for controlling and shifting gearing for varying the pitch of a variable pitch propeller, the combination ofl a' governor body provided with inlet and voutlet passages for uid, a gear pump in the body for forcing uid to control said gearing, a valve'in the body for controlling the pressure otuid to said gearing, iluid pressure means in said body for controlling the governor valve, a manually controlled valve for controlling the pressure of iluid for operating said means, and means associated \with said valve responsive to thermal changes for compensatingfor variations in viscosity and temperature of` the fluid passing the valve.

10. In uid pressure means for controlling and shifting gearing for varying the pitch ofV a variable pitch-propeller, the combination of a governor body provided with inlet and outlet passages for fluid, a gear pump in the body for forcing iluid to control said gearing, a valve in the body for controlling the pressure of iluid to said gearing, iluidpressure means insaid body for controlling the governor valve, a manually controlled valve for controlling the pressure of fluid for operating said means, a yieldable seat,

and thermal responsive means for compensating for variations in viscosity and temperatur of the fluid passing the valve. p

11. Mechanism for shifting and controlling the blades of a variable pitch propeller, comprising variable speed gearing for shifting the blades to vary their pitch which includes a driving ele.. ment, a driven element, and means for varying the ratio of the speed of the driven element to the driving element, uuid-pressure means for actuating the gearing [for pitch-changes, a. uidpressure pump responsive to the speed of the propeller, and means tov which the pump is hydraulically connected, for inuencing said -iirstnamed uuid-pressure means to effect an increase of pitch by varying speed ratios of the driven-,element to the driving element, said gearing in response to an increase of pressure and a decrease of pitch by varying speed ratios of the driven element to the driving element in response to a decrease of pressure by the uuidpressure pump.

12. Mechanism for shifting andcontrolling the blades of a variable pitch propeller, comprising variable speed gearing for shifting the blades to vary their pitch which includes a driving element, a driven element, and means for Varying the ratios of the speed of the driven element to the driving element, fluid-pressure means for actuating the gearing for pitchchanges, a uuid-pressure pump responsive to the speed oi the propeller, means to which the `pump is hydraulically connected for influencing said Airst--nained duid-pressure means to effect an increase of pitch by varying speed ratios of -the driven element to the driving element in response to an increase of pressure and a decrease of pitch by varying speed ratios of the driven element to the driving element in response to a decrease of pressure by the fluid-pressure pump,

and means for predeterminately varying the operation of said influencing means by the pump. 13. Mechanism for shifting and controlling the blades of a, variable pitch propeller, comprisingvariable speed gearing for shifting the blades to vary their pitch which includes a driving ele'- ment, a driven element, and means for varying the ratio of the speed of the driven element to theldriving element, fluidfpressure means for actuating the gearing for pitch-changes, a Auidpressure pump responsive to the speed of the propeller, means to which the pump is hydraulically controlled for influencing said first-named Huid-pressure means to effect an increase of pitch by varying speed ratios of the driven element to the driving element in response to an increase of pressure by the pump and a decrease of pitch by varying speed ratios of the driven element to the driving element in response to a decrease of pressure by the pump, and a man ually-controlled valve for rendering the uidpressure means inoperative for operation of the blade at a xed pitch.

GLEN T. LAMIPTON.

PAUL F. HACKETHAL. ARTHUR T. BRIGGS. 

